{"paper":{"title":"Effect of Helium Sedimentation on X-ray Measurements of Galaxy Clusters","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph","authors_text":"Daisuke Nagai, Fang Peng","submitted_at":"2008-08-27T20:00:31Z","abstract_excerpt":"The uniformity of the helium-to-hydrogen abundance ratio in X-ray emitting intracluster medium (ICM) is one of the commonly adopted assumptions in X-ray analyses of galaxy clusters and cosmological constraints derived from these measurements. In this work, we investigate the effect of He sedimentation on X-ray measurements of galaxy clusters in order to assess this assumption and associated systematic uncertainties. By solving a set of flow equations for a H-He plasma, we show that the helium-to-hydrogen mass ratio is significantly enhanced in the inner regions of clusters. The effect of He se"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"0808.3769","kind":"arxiv","version":3},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}